The centrosome is a cellular organelle that functions as the microtubule organizing center of interphase and mitotic cells (Nigg (2002)). The centrosome duplicates itself only once during each cell cycle with duplication beginning near the G1-S transition and completing during the G2 phase. Duplicated centrosomes separate to produce two mitotic spindle poles that organize the mitotic apparatus. Centrosomes play critical roles in processes that ensure proper segregation of chromosomes and maintain the genetic stability of human cells (Shinmura et al. (2008); Fukasawa (2007)). Centrosomal defects were originally proposed to lead to aneuploidy and cancer in 1914 by Boveri (Wunderlich (2002); Brinkley et al. (1998)). He saw that cancer cells commonly have centrosomal defects including increased centrosome number and postulated that changes in centrosome functionality may be key to cancer formation. Centrosomal abnormalities are detected in various types of human cancers, e.g., cancers of the lung, breast, gall bladder, bone, pancreas, colorectal, head, neck, prostate and ovaries (Bourke et al. (2007); Saunders (2005)) and rarely observed in normal tissue (Saunders (2005)). It is believed that cancer cells commonly have centrosomal defects. Most researches have found that centrosomal defects occurred at a very early premalignant stage of tumor formation, prior to the appearance of detectable lesions. Centrosomal defects have been found to increase in severity during tumor progression. Recent evidence indicates that loss of centrosomal integrity may be a major cause of chromosomal instability underlying various human cancers (Fukasawa (2007); Bourke et al. (2007); Lentini et al. (2007); Landen et al. (2007)). Aneuploidy of nonsmall cell lung cancer is associated with centrosomal abnormalities (Jung et al. (2007)). In the lung, important findings suggest that centrosomal abnormalities may develop at a relatively early stage of lung carcinogenesis. Moreover, it was shown that stepwise progression of centrosome defects is associated with local lung tumor progression to a more advanced stage, and with accelerating the metastatic process of lung carcinoma cells (Koutsami et al. (2006)).
Lung cancer is the most common cause of cancer mortality for both men and women. In 2009, the American Cancer Society estimated the numbers of lung cancer cases were 219,440 and lung cancer resulted in 159,390 deaths in the United States (Jemal et al. (2009)). In contrast, colorectal, breast, and prostate cancers combined were 117,890 deaths. Once diagnosed, prognosis and treatment depend upon lung cancer staging, which considers tumor size and extent, nodal involvement and distant metastasis (AJCC, (1998)). The five-year survival rates by clinical stages were IA 50%, IB 47%, IIA 36%, IIB 26%, IIIA 19%, IIIB 7%, and IV 2% (Rami-Porta et al. (2009)). Cancer detected in early stages have higher survival rate. Unfortunately, the prognosis of stage I lung cancer is highly variable. Post operative recurrence of stage I non-small cell lung carcinoma (NSCLC) leads to early mortality in approximately 40%, with current pathology indices unable to distinguish those with poor prognosis (Woo, (2009)). In our preliminary data (35 cases), there are four cases who have survived nine years or more (still alive) and three deceased cases who survived four years or less (four, three, and two years, respectively) in stage IA; there are two cases who've survived nine years or more (remain alive) and six deceased cases who survived four years or less (one case survived less than one year, two cases survived one year, three cases survived four, three, two years, respectively) in stage IB. In our study of patients with stage I lung cancer, clinical techniques could not distinguish stage I patients into long term survivors and short term survival (fatality) groups. Molecular prognostic and diagnostic cancer markers should have a high prevalence, and the techniques to measure these markers must have high sensitivity and specificity. Examination of tumor cell organelles or markers can provide a method to accurately diagnose and recognize the prognosis of individual stage I NSCLC to enable timely and personalized administration of therapy (Kwiatkowski et al. (1998); D'Amico et al. (2000); D'Amico (2002)).